Updates in Culture-Negative Endocarditis

Innovative Management of Blood Culture-Negative Endocarditis With Pulmonary Septic Emboli in a Patient With a Biventricular Pacemaker and Implantable Cardioverter Defibrillator (BiV-ICD) and Psychosocial Stressors: A Case Report

Blood culture-negative endocarditis (BCNE) poses significant diagnostic and therapeutic challenges and is associated with notable morbidity and mortality. When presented concurrently with other comorbidities, these challenges and the chances of morbidity and mortality significantly increase. This case presents right-sided BCNE accompanied by pulmonary cavitary lesions in a patient with a history of supraventricular tachycardias (SVT), a biventricular pacemaker and implantable cardioverter-defibrillator (BiV-ICD), alcohol use, and anticoagulant noncompliance. The patient missed follow-up appointments for six months after the death of his wife, leading to increased alcohol use and noncompliance with medications. During this period, his home monitoring device was offline. Once reconnected, it detected several episodes of SVT and ventricular tachycardia (VT), prompting a wellness check. He presented to the cardiology clinic with shortness of breath and a cough producing brown-tinged sputum. Evaluation revealed cavitary lesions in the lingula and left lower lobe, a vegetation on his tricuspid valve, and vegetations on his endocardial leads, despite negative blood cultures. Tuberculosis testing was negative, while sputum cultures were positive for Haemophilus influenzae. After ruling out other possible infectious causes of the cavitary lesions, septic emboli were suspected as the cause. Broad-spectrum antibiotics were begun and surgical intervention was done to replace the tricuspid valve and remove the endocardial leads. This procedure was complicated by fibrosis of the leads at the coronary sinus, necessitating their cutting at the superior vena cava and leaving them inside the patient until laser therapy could be performed for their removal. The patient's history of bradycardia and SVTs required the ongoing use of a pacemaker. Inventory discrepancy during the placement of the new pacemaker epicardial leads lead to complications warranting an alternative approach to lead implantation. A traditionally used epicardial lead was placed on the right ventricle for pacing, and an innovative technique was employed to place an endocardial lead on the right atrium epicardium for sensing. This case underscores the importance of thorough evaluation and collaborative management strategies to optimize outcomes for patients with concomitant cardiac and pulmonary pathologies, particularly in the context of underlying psychosocial stressors. Additionally, it demonstrates solutions to challenges that can arise during surgery and presents an alternative lead placement technique for physicians who have only one epicardial lead available after removing infected endocardial leads. This is illustrated by the innovative use of an endocardial lead as an epicardial sensing lead.

Emerging and Re-Emerging Pathogens in Valvular Infective Endocarditis: A Review

Infective endocarditis (IE) is a microbial infection of the endocardial surface, most commonly affecting native and prosthetic valves of the heart. The epidemiology and etiology of the disease have evolved significantly over the last decades. With a growing elderly population, the incidence of degenerative valvopathies and the use of prosthetic heart valves have increased, becoming the most important predisposing risk factors. This change in the epidemiology has caused a shift in the underlying microbiology of the disease, with Staphylococci overtaking Streptococci as the main causative pathogens. Other rarer microbes, including Streptococcus agalactiae, Pseudomonas aeruginosa, Coxiella burnetti and Brucella, have also emerged or re-emerged. Valvular IE caused by these pathogens, especially Staphylococcus aureus, is often associated with a severe clinical course, leading to high rates of morbidity and mortality. Therefore, prompt diagnosis and management are crucial. Due to the high virulence of these pathogens and an increased incidence of antimicrobial resistances, surgical valve repair or replacement is often necessary. As the epidemiology and etiology of valvular IE continue to evolve, the diagnostic methods and therapies need to be progressively advanced to ensure satisfactory clinical outcomes.

Fostering Collaborative Teamwork-A Comprehensive Approach to Vascular Graft Infection Following Arterial Reconstructive Surgery

Vascular graft infection (VGI) is one of the most serious complications following arterial reconstructive surgery. VGI has received increasing attention over the past decade, but many questions remain regarding its diagnosis and management. In this review, we describe our approach to VGI through multidisciplinary collaboration and discuss decision making for challenging presentations. This review will concentrate on VGI that impacts both aneurysms and pseudoaneurysms excluding the ascending thoracic aorta.

A 'Decrescendo' in a Woman With Ascending Paralysis: A Diagnostic Challenge

Guillain-Barre Syndrome (GBS) is an autoimmune condition that causes muscular weakness and can be potentially life-threatening if not identified early. GBS is diagnosed definitively by cerebrospinal fluid (CSF) analysis and electromyographic (EMG) studies. Identifying illnesses that may have triggered GBS is crucial, as they could affect the course of the disease. Our patient was a 27-year-old woman who developed lower extremity weakness a few days after being treated for a dental abscess. Laboratory and imaging studies ruled out central nervous system (CNS) lesions, myelopathies, and metabolic causes. Diagnosis was difficult due to inconclusive initial investigations, refusal of lumbar puncture, and delayed availability of EMG studies. Additionally, there were no identifiable triggers to support GBS as a diagnosis. During the hospital course, the patient developed tachycardia with new electrocardiogram (EKG) changes. A transthoracic echocardiogram (TTE) showed suspicious vegetation, and a transesophageal echocardiogram (TEE) confirmed severe mitral regurgitation. The new valvular lesions and autonomic dysfunction with worsening lower extremity weakness increased our suspicion of GBS. Intravenous immunoglobulin (IVIG) was administered empirically, but she developed bulbar symptoms, prompting admission to the intensive care unit (ICU). A lumbar puncture performed at this time was negative for albumino-cytological dissociation and CNS infections.  Signs of sepsis with valvular lesions raised concerns for infective endocarditis (IE). Due to recent treatment with antibiotics for dental abscess, a negative blood culture was a confounding factor in Duke's criteria, delaying the diagnosis of IE. Infectious disease experts suggested empirical treatment for suspected blood culture-negative infective endocarditis (BCNE) and valvular abscess. She was transferred to a cardiothoracic care facility for valvular surgery evaluation. EMG studies identified the patient's condition as the acute motor sensory axonal neuropathy (AMSAN) variant of GBS. The patient's antibodies tested positive for Campylobacter jejuni (C. Jejuni) immunoglobulin G (IgG). Since this indicates a past infection, it is uncertain whether C. Jejuni triggered the patient's GBS. However, new valvular vegetation and acute-onset lower extremity weakness make us hypothesize that BCNE may have triggered GBS.

Antimicrobial susceptibility of Viridians Group of Streptococci isolated from infective endocarditis patients from 2018 to 2023

INTRODUCTION

Viridans Group of Streptococci (VGS) are heterogeneous alpha hemolytic Streptococci that form commensal flora in the oral cavity, upper respiratory tract, gastrointestinal tract and female genital tract and are potential pathogens that can cause serious infections like infective endocarditis and bacteremia. Penicillin or Ceftriaxone is the recommended first line agent for definitive therapy of VGS endocarditis. Alteration in penicillin binding proteins can decrease the susceptibility of VGS to penicillin and other beta-lactam agents and complicate antimicrobial therapy for serious VGS infections like Infective endocarditis. The aim of our study was to determine the antimicrobial susceptibility pattern of viridians group Streptococci isolated from blood samples of infective endocarditis patients from April 2018 to September 2023 against betalactam and other agents.

MATERIAL AND METHODS

Three sets of blood cultures with 8-10 ml per bottle were collected from suspected infective endocarditis and incubated in automated blood culture system (BACTEC from BD diagnostics). The broth from positive bottles was streaked on Blood agar, Chocolate agar and MacConkey agar plates and incubated at 37°C. Alpha hemolytic Streptococci that grew after 24-48 h were further identified and antimicrobial susceptibility determined by Vitek 2 system.

RESULTS

A total of 100 VGS was isolated from blood samples of Infective endocarditis patients. The species most commonly isolated in our study was S. sanguinis (25%) and S.mitis/oralis group (23%) followed by Non speciated Viridans Streptococci (17%). The lowest penicillin susceptibility ie. PEN MIC <0.12 μg/ml of 40% was observed in S. alactolyticus group, followed by S. mitis (52%) and S. gallolyticus (56%). S. mitis/oralis group showed the lowest susceptibilities to betalactam antibiotics among all speciated and non speciated VGS.

CONCLUSION

Infective endocarditis carries a very high mortality and morbidity and the emergence of resistance to betalactam agents like penicillin will only narrow available therapeutic options and further challenge the treatment.

Novel Diagnostic Methods for Infective Endocarditis

Infective endocarditis (IE) remains a dangerous disease and continues to have a high mortality rate. Unfortunately, despite continuous improvements in diagnostic methods, in many cases, blood cultures remain negative, and the pathogen causing endocarditis is unknown. This makes targeted therapy and the selection of appropriate antibiotics impossible. Therefore, we present what methods can be used to identify the pathogen in infective endocarditis. These are mainly molecular methods, including PCR and MGS, as well as imaging methods using radiotracers, which offer more possibilities for diagnosing IE. However, they are still not widely used in the diagnosis of IE. The article summarizes in which cases we should choose them and what we are most hopeful about in further research into the diagnosis of IE. In addition, registered clinical trials that are currently underway for the diagnosis of IE are also presented.

Influence of filtering on the effective concentration and sterility of a 2% cyclosporine ophthalmic solution: a quality improvement perspective

BACKGROUND

Pharmaceutical companies do not sell formulations for all diseases; thus, healthcare workers have to treat some diseases by concocting in-hospital preparations. An example is the high-concentration 2% cyclosporine A (CyA) ophthalmic solution. Utilizing a filter in sterility operations is a general practice for concocting in-hospital preparations, as is the case for preparing a 2% CyA ophthalmic solution. However, whether filtering is appropriate concerning the active ingredient content and bacterial contamination according to the post-preparing quality control of a 2% CyA ophthalmic solution is yet to be verified.

METHODS

We conducted particle size, preparation concentration, and bacterial contamination studies to clarify aforementioned questions. First, we measured the particle size of CyA through a laser diffraction particle size distribution. Next, we measured the concentration after preparation with or without a 0.45-µm filter operation using an electrochemiluminescence immunoassay. Finally, bacterial contamination tests were conducted using an automated blood culture system to prepare a 2% CyA ophthalmic solution without a 0.45 μm filtering. Regarding the pore size of the filter in this study, it was set to 0.45 μm with reference to the book (the 6th edition) with recipes for the preparation of in-hospital preparations edited by the Japanese Society of Hospital Pharmacists.

RESULTS

CyA had various particle sizes; approximately 30% of the total particles exceeded 0.45 μm. The mean ± standard deviation of filtered and non-filtered CyA concentrations in ophthalmic solutions were 346.51 ± 170.76 and 499.74 ± 76.95ng/mL, respectively (p = 0.011). Regarding bacterial contamination tests, aerobes and anaerobes microorganisms were not detected in 14 days of culture.

CONCLUSIONS

Due to the results of this study, the concentration of CyA may be reduced by using a 0.45-µm filter during the preparation of CyA ophthalmic solutions, and furthermore that the use of a 0.45-µm filter may not contribute to sterility when preparing CyA ophthalmic solutions.